The 10Oz Printed Cup is gentle on tender gums and emerging teeth. As a child puts lip pressure on the straw, the touch flow valve opens, and water flows. When the child stops sipping, the valve closes. The Nuby Printed Cup is designed to prevent drips and spills. When drinking, the one-piece touch flow valve opens so liquids pass through the straw only when your child sips. Soft Silicone Spout is made from the same safe, soft silicone material as nuby nipples, your child is comfortable with the feel and function of these no-spill spouts. While the unique contour shape easily fits their small hands, the spout is still gentle on your child's tender gums and emerging teeth. The one-piece built-in valve controls the liquid's flow rate.